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Search Results: 1 - 10 of 31665 matches for " JUAN PARITSIS "
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Temperature and foliage quality affect performance of the outbreak defoliator Ormiscodes amphimone (F.) (Lepidoptera: Saturniidae) in northwestern Patagonia, Argentina
PARITSIS,JUAN; VEBLEN,THOMAS T;
Revista chilena de historia natural , 2010, DOI: 10.4067/S0716-078X2010000400012
Abstract: in the temperate forests of chile and argentina the phytophagous moth ormiscodes amphimone (f.) causes severe defoliation on the southern beech tree nothofagus pumilio (poepp. & endl.) krasser. the recent increase in defoliation frequency in some áreas appears to be influenced by a warmer climate. to evalúate the effects of temperature and the spatial heterogeneity of foliage quality on the performance and relative consumption rate of o. amphimone in northwestern patagonia, argentina we conducted a factorial experiment. larval performance was measured as relative growth rate, developmental time, larval survival, and pupal weight. larvae of o. amphimone were reared under two constant temperature regimes (15 °c and 20 °c) and fed with two n. pumilio foliage types (from a mesic and from a xeric site). larvae at the higher temperature and fed with leaves from the mesic site showed higher performance and consumption rate than larvae in the other treatments. higher temperature and mesic foliage had positive effects on o. amphimone's relative growth rate, development time and relative consumption rate. however, pupal weight was positively influenced by mesic foliage but not by temperature, and larval survival did not show significant differences among treatments. our results preliminarily suggest that o. amphimone performance and consumption rate may increase under higher temperature conditions, especially in the mesic portions of the precipitation gradient. however, these findings should be carefully interpreted as further research is necessary to assess the influence of higher temperatures on the foliar quality of n. pumilio.
Temperature and foliage quality affect performance of the outbreak defoliator Ormiscodes amphimone (F.) (Lepidoptera: Saturniidae) in northwestern Patagonia, Argentina La temperatura y la calidad del follaje afectan el desempe o del defoliador epidémico Ormiscodes amphimone (F.) (Lepidoptera: Saturniidae) en el noroeste de la Patagonia argentina
JUAN PARITSIS,THOMAS T VEBLEN
Revista chilena de historia natural , 2010,
Abstract: In the temperate forests of Chile and Argentina the phytophagous moth Ormiscodes amphimone (F.) causes severe defoliation on the southern beech tree Nothofagus pumilio (Poepp. & Endl.) Krasser. The recent increase in defoliation frequency in some áreas appears to be influenced by a warmer climate. To evalúate the effects of temperature and the spatial heterogeneity of foliage quality on the performance and relative consumption rate of O. amphimone in northwestern Patagonia, Argentina we conducted a factorial experiment. Larval performance was measured as relative growth rate, developmental time, larval survival, and pupal weight. Larvae of O. amphimone were reared under two constant temperature regimes (15 °C and 20 °C) and fed with two N. pumilio foliage types (from a mesic and from a xeric site). Larvae at the higher temperature and fed with leaves from the mesic site showed higher performance and consumption rate than larvae in the other treatments. Higher temperature and mesic foliage had positive effects on O. amphimone's relative growth rate, development time and relative consumption rate. However, pupal weight was positively influenced by mesic foliage but not by temperature, and larval survival did not show significant differences among treatments. Our results preliminarily suggest that O. amphimone performance and consumption rate may increase under higher temperature conditions, especially in the mesic portions of the precipitation gradient. However, these findings should be carefully interpreted as further research is necessary to assess the influence of higher temperatures on the foliar quality of N. pumilio. En los bosques templados de Chile y Argentina la polilla fitófaga Ormiscodes amphimone (F.) genera severas defoliaciones sobre la lenga (Nothofagus pumilio [Poepp. & Endl.] Krasser). El reciente aumento en la frecuencia de defoliación en algunas áreas de la Patagonia parecería estar influenciada por un clima más cálido. Para evaluar los efectos de la temperatura y la heterogeneidad espacial en la calidad del follaje sobre el desempe o y la tasa de consumo relativo del defoliador O. amphimone en el noroeste de la Patagonia argentina llevamos a cabo un experimento factorial. El desempe o larval fue medido como tasa de crecimiento relativo, tiempo de desarrollo, supervivencia larval y peso de las pupas. Las larvas de O. amphimone fueron criadas bajo dos temperaturas constantes (15 °C y 20 °C) y alimentadas con dos tipos de follaje de N. pumilio (de un sitio mésico y de uno xérico). Las larvas criadas a la temperatura más alta y alimentadas
New host-plant records for the defoliator Ormiscodes amphimone (Fabricius) (Lepidoptera: Saturniidae)
Paritsis, Juan;Elgueta, Mario;Quintero, Carolina;Veblen, Thomas T;
Neotropical Entomology , 2010, DOI: 10.1590/S1519-566X2010000600032
Abstract: ormiscodes amphimone (fabricius) is a phytophagous moth species known to severely defoliate woody species in chile and argentina. here we document new records of o. amphimonehost associations emphasizing the role of nothofagus pumilio as its primary host in our study area. this new record for argentina is highly significant given the economic importance of n. pumilio as a timber resource and the potential of o. amphimone to generate extensive outbreaks.
Mortality of the outbreak defoliator Ormiscodes amphimone (Lepidoptera: Saturniidae) caused by natural enemies in northwestern Patagonia, Argentina
PARITSIS,JUAN; QUINTERO,CAROLINA; KITZBERGER,THOMAS; VEBLEN,THOMAS T;
Revista chilena de historia natural , 2012, DOI: 10.4067/S0716-078X2012000100009
Abstract: outbreaks of the defoliator moth ormiscodes amphimone are occurring more frequently in numerous nothofagus forests of patagonia. however, little is known about the life history of this species including its natural enemies as mortality agents. in this work we quantified mortality by parasitoids and generalist predators at the egg, larval and pupal life stages of o. amphimone in a nothofagus pumilio (poepp. & endl.) krasser forest in northwestern patagonia. parasitism of eggs was relatively low (ca. 11 %), and we did not record significant larval predation by insectivorous birds. however, we recorded elevated mortality caused by larval parasitoids (ca. 50 % in third instar larvae) and pupal predators (ca. 75 %), which suggests that these natural enemies could play a significant role in regulating o. amphimone populations. our research is an initial step towards understanding the influence of natural enemies on o. amphimone population dynamics.
Mortality of the outbreak defoliator Ormiscodes amphimone (Lepidoptera: Saturniidae) caused by natural enemies in northwestern Patagonia, Argentina Mortalidad del defoliador epidémico Ormiscodes amphimone (Lepidoptera: Saturniidae) causada por enemigos naturales en el noroeste de la Patagonia Argentina
JUAN PARITSIS,CAROLINA QUINTERO,THOMAS KITZBERGER,THOMAS T VEBLEN
Revista chilena de historia natural , 2012,
Abstract: Outbreaks of the defoliator moth Ormiscodes amphimone are occurring more frequently in numerous Nothofagus forests of Patagonia. However, little is known about the life history of this species including its natural enemies as mortality agents. In this work we quantified mortality by parasitoids and generalist predators at the egg, larval and pupal life stages of O. amphimone in a Nothofagus pumilio (Poepp. & Endl.) Krasser forest in northwestern Patagonia. Parasitism of eggs was relatively low (ca. 11 %), and we did not record significant larval predation by insectivorous birds. However, we recorded elevated mortality caused by larval parasitoids (ca. 50 % in third instar larvae) and pupal predators (ca. 75 %), which suggests that these natural enemies could play a significant role in regulating O. amphimone populations. Our research is an initial step towards understanding the influence of natural enemies on O. amphimone population dynamics. Las irrupciones poblacionales de la polilla defoliadora Ormiscodes amphimone están ocurriendo de manera más frecuente en numerosos bosques de Nothofagus de la Patagonia. Sin embargo, se sabe poco de la historia natural de esta especie y, particularmente, de sus enemigos naturales. En este estudio se cuantificó la depredación de huevos, larvas y pupas de O. amphimone por parasitoides y otros depredadores en un bosque de Nothofagus pumilio (Poepp. & Endl.) Krasser en el noroeste de la Patagonia. Se encontró que el parasitismo de huevos fue relativamente bajo (ca. 11 %) y no se registró depredación significativa de larvas por aves insectívoras. No obstante, registramos niveles elevados de mortalidad causada por parasitoides de larvas (ca. 50 % en larvas en tercer instar) y por depredadores de pupas (ca. 75 %), lo que parece indicar que estos enemigos naturales desempe an un papel significativo en la regulación de poblaciones de O. amphimone. Este estudio representa un paso inicial hacia el entendimiento de la influencia de los enemigos naturales de O. amphimone en la dinámica de poblaciones de esta polilla.
Summary on the Studies of the Unearthed Bamboo Medical Books for the Past Forty Years
—Take Prescriptions of Fifty-Two Diseases and Han Medical Books of Wuwei for Example
 [PDF]

Juan Hu
Chinese Studies (ChnStd) , 2016, DOI: 10.4236/chnstd.2016.51001
Abstract: For the past forty years, the study of the unearthed bamboo medical books has always been a very valid concern and many important achievements have yet been achieved. However, the lack of standard handwriting in addition to seriously being destroyed when unearthed, it’s not that easy to read them. The purpose of this article is to sort through and correct some commonly occurred interpretation mistakes from the previous studies.
An Efficient Method to Reduce the Numerical Dispersion in the HIE-FDTD Scheme  [PDF]
Juan Chen, Anxue Zhang
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.21005
Abstract: A parameter optimized approach for reducing the numerical dispersion of the 3-D hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) is presented in this letter. By adding a parameter into the HIE-FDTD formulas, the error of the numerical phase velocity can be controlled, causing the numerical dispersion to decrease significantly. The numerical stability and dispersion relation are presented analytically, and numerical experiments are given to substantiate the proposed method.
Centralized Quasi-Static Channel Assignment for Multi-Radio Multi-Channel Wireless Mesh Networks  [PDF]
Juan REN, Zhengding QIU
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.12016
Abstract: Employing multiple channels in wireless multihop networks is regarded as an effective approach to increas-ing network capacity. This paper presents a centralized quasi-static channel assignment for multi-radio multi-channel Wireless Mesh Networks (WMNs). The proposed channel assignment can efficiently utilize multiple channels with only 2 radios equipped on each mesh router. In the scheme, the network end-to-end traffics are first modeled by probing data at wireless access points, and then the traffic load between each pair of neighboring routers is further estimated using an interference-aware estimation algorithm. Having knowledge of the expected link load, the scheme assigns channels to each radio with the objective of mini-mizing network interference, which as a result greatly improves network capacity. The performance evalua-tion shows that the proposed scheme is highly responsive to varying traffic conditions, and the network per-formance under the channel assignment significantly outperforms the single-radio IEEE 802.11 network as well as the 2-radio WMN with static 2 channels.
Embedding PV and WF Models into Steady State Studies by an Optimization Strategy  [PDF]
Juan Manuel Ramirez
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.23027
Abstract: Modeling of photovoltaic (PV) and wind farms (WF) stations to take into account these renewable energies into the power flow formulation are summarized. A strategy based on multi objective optimization in order to allocate PV and WF power into electrical power system is proposed. It is assumed that there are a reduced number of choices to allocate the stations. The algorithm is applied to the 39-bus test power system. The results show that the proposed algorithm is capable of optimal placement of renewable units.
Fabrication of Poly(Aspartic Acid)-Nanogold Modified Electrode and Its Application for Simultaneous Determination of Dopamine, Ascorbic Acid, and Uric Acid  [PDF]
Juan Li, Xiaoli Zhang
American Journal of Analytical Chemistry (AJAC) , 2012, DOI: 10.4236/ajac.2012.33028
Abstract: A nanostructured polymer film incorporated gold nanoparticles modified electrode was fabricated. The fabrication process involved a previous electropolymerization of aspartic acid and followed by the eletrodeposition of gold nano-particles on the glassy carbon electrode. The resulting poly (aspartic acid)-nanogold modified electrode (PAA- nano-Au/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectros-copy (EIS). A higher catalytic activity was obtained to electrocatalytic oxidation of dopamine (DA), ascorbic acid (AA) and uric acid (UA) due to the enhanced peak current and well-defined peak separations compared with three, bare GCE, PAA/GCE and nano-Au/GCE. Simultaneous determination of DA, AA, and UA were studied by voltammetry. The linear range of 5.0 × 10-7 - 1.0 × 10-4 M for DA, 5.0 × 10-6 - 2.0 × 10-3 M for AA and 5.0 × 10-6 - 1.0 × 10-3 M for UA was obtained. The detection limit was calculated for DA, AA and UA as being 6.5 × 10-8 M, 5.6 × 10-7 M and 3.0 × 10-7 M, respectively (S/N = 3). The practical application of the present modified electrode was demonstrated by the determination of DA, AA and UA in calf serum and fetal calf serum samples.
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